SA2B Physics
Speed limits Sonic Adventure 2 will not allow a velocity value greater than '16' along the three spacial axes. This is the 'hard cardinal speed-limit,' applying to all known scenarios (aside from rail grinding as Speed characters). This hard speed-limit is unrelated to Terminal Velocity, or to character Gravity/Rotation. This means that you may not exceed 16 in-game units following the X, Y, or Z axis. If Sonic has normal gravity, and velocity values of X=16 and Z=16, his relative "forward" velocity will read as 22.627 (16 × √2). If Sonic has normal gravity, and velocity values of X=16, Y=16, and Z=16, his "total" velocity will read as 27.713 (16 × √3). (With skewed gravity, it is technically possible to have 27.713 as Sonic's relative forward velocity, as opposed to total velocity. It similar also could be possible for Sonic's relative upward/downward velocity to reach 27.713). Terminal velocity is character and stage dependent, and only applies to negative vertical speed, specifically when it ceases to increase while falling (or decreases when exceeded). Terminal Velocity by character/stage: Hover Hover is a mechanic in Sonic Adventure 2 which allows you to temporarily slow the rate of vertical deceleration while jumping. Spindash hover The hover variable Midair pause hover Speedshoes Stacking speedshoes Abusing moving objects Moving objects which can be stood on in Sonic Adventure 2 will add (a portion of?) their momentum to your character’s current speed when jumped off of. This can be a hindrance if the object is moving backwards, and very useful if moving forwards. Hunting characters in particular can exploit this to absurd degrees (more on this later), though there are very few moving objects, if any, in most of their stages. Death abuse Dying via killplane (not damage) will not immediately disable control over your character, but it does pause the ingame timer. This means in select situations, when the goal is to optimize in-game time, you can use deaths before touching checkpoints, or finishing a stage, to stop the timer sooner. There are also permanent timestop glitches possible with Tails and Eggman in Hidden Base and Sand Ocean by using the quicksand and a conveniently placed spring. Animation canceling Most actions, like mystic melody, immediately activate, but have very long animations. You can interrupt animations with things such as damage (or springs? Other things?). Some actions, like treasure scope and sunglasses, do not activate instantly but rather midway into the animation, these can still be canceled but a useful result will only happen if canceled after the activation. Bypassing Killplanes At the moment, bypassing killplanes is only known to exist in one area: Final Rush. The “Fast Final Rush skip” in particular. The reason this trick works is actually quite simple, and opens the door to similar skips elsewhere in the game.. If only the conditions were meet somewhere else. Unlike some other games, Sonic Adventure 2 seems to only check character position on each frame, and pays no attention to area covered between frames. Because killplanes don’t have collision, and only check position, if they’re made thin enough, it’s actually possible to be in front of, but not touching it, for one frame; and to be behind, and also not touching it, on the next frame. The only requirement is that you’re moving at a speed faster than the width of the trigger, and that you’re aligned such that you never appear inside the trigger. Unfortunately, most killplane triggers are much too thick for this to be possible, and because of the universal aerial speed limit, anything thicker than 16 would seem physically impossible to bypass. The majority of killplanes are well over 16 units thick, it just so happens that the final rush one is only approximately __(4.5 I think) units thick. Gravity Rotation system Maintaining gravity =